1. Field of the Invention
This invention relates generally to inlet leaks for sampling gases and more particularly to a fluid sampling device for selectively sampling multiple fluids.
2. Description of the Prior Art
Inlet leaks are highly useful and extensively used for introducing a fluid such as, for example, a gas into a mass spectrometer or other devices for analyzing a gas in a particular environment.
Present day devices utilize a single inlet leak tube constructed of glass having a capillary opening extending through the glass tube. The inlet leak is inserted into a mass spectrometer or other gas analyzers. The apparatus is placed within the gas to be analyzed and the gas is allowed to flow through the inlet leak into the gas analyzer where the characteristics of the gas can be broken down and studied. This device works exceptionally well where a single particular gas is to be analyzed.
In certain environmental situations the above device has many disadvantages because a single inlet tube can only be used once since it is contaminated by the gas that has been sampled. A use where such prior art devices is unsuitable involve sampling of multiple gases at different locations. If the above prior art devices are used, the sample taken at the first location can be analyzed correctly, however, subsequent samples taken at different locations will be contaminated by the residue gas from the first location. This will prevent a true analysis of the gases at the subsequent locations. Thus, the inlet leak tube can only be used once or only be used to analyze the same gas again and once the inlet leak tube is opened gases will continue to flow into the analyzer.
To take multiple samples of gases without contamination by the previously sampled gas it is necessary to replace the used inlet leak tube with an unused inlet leak tube and the analyzer must be pumped out to remove the residual gases or a plurality of gas analyzers may be used having a single uncontaminated inlet leak tube. In many situations the above multiple sampling technique cannot be used or are impractical and expensive. An exemplary situations is where the gas samples in a planets atmosphere must be taken at different heights above the planets surface. Since planet probes are unmanned, it would be difficult to provide for the replacement of the inlet leak tube after each gas sample is taken, and because of size and weight limitations on a spacecraft multiple gas analyzers having a single one-shot inlet leak tube cannot be used.
Another situation where the above prior art devices are unfeasible is in analyzing the different gases emitted by a volcano at various heights and at different times within the volcano. Time is of the essence when working around an active volcano and it is therefore desirable to obtain and analyze the gas samples as quickly as possible. The above prior art devices do not lend themselves to such rapid sampling.